For use in a loose leaf binder, paper sheets having holes perforated in advance therein at prescribed positions are available in the market. A user of the loose leaf binder, therefore, is free to purchase these perforated paper sheets and file them in the loose leaf binder. There are times, however, when he is compelled to file in the loose leaf binder reproduced copies and catalogs which have no perforations at all.
The conventional multi-hole punch intended for punching holes in such unperforated paper sheets so that they may be filed in the loose leaf binder is so voluminous as to occupy much space and too expensive to find widespread acceptance. Thus, most users of loose leaf binders have been forced to endure the great inconvenience involved in punching as many holes in paper sheets as desired by the use of a one-hole punch, for example. Such devices are described in Japanese Utility Model Application No. SHO 54(1979)-116466, Japanese Utility Model Application No. SHO 54(1979)-127930, etc.
These perforators share a basic construction in which a one- or two-hole punch is provided in the front portion thereof with projections or depressions and possesses on the upper or lower side of these projections or depressions a recess extended from the front end to the rear end and adapted to receive insertion of superposed paper sheets. Separate from the punch are two oblong sheet retainer plates, one disposed on top of the other, with the longitudinal ends thereof pivotally attached to each other. A perforation jig is included which is provided therein with a plurality of punch-positioning depressions or projections, adapted to engage respectively with the projections or depressions of the aforementioned punch and spaced at fixed intervals along the longitudinal edge of either of the two oblong sheet retainer plates or along the longitudinal edge of the pivotally attached side of either or both of the two superposed sheet retainer plates.
With the perforator of this construction, paper sheets are neatly arranged by a sheet positioner attachably disposed on the aforementioned perforation jig and are then held fast in position between the two sheet retainer plates, with the leading ends of the paper sheets protruding from the side of the jig on which the punch-positioning depressions or projections are disposed. The punch is abutted against the protruding ends of the paper sheets so that the recess in the front side of the punch may receive the leading ends of the paper sheets and the projections or depressions in the front portion of the punch will come into engagement with the punch-positioning depressions or projections on the jig. In this manner, as many holes as desired may be perforated at prescribed positions in the paper sheets.
This perforator, however, has the disadvantage that the punch secured in position with respect to the paper sheets still has freedom of motion with respect to the perforator, except for that portion of the perforator in which the projections or depressions in the front portion of the punch are fast engaged with the punch-positioning depressions or projections on the perforation jig. Thus the depressing force exerted upon the lever of the punch in the course of perforation will cause the punch itself to shake or vibrate in the vertical direction relative to the perforation jig possibly to the extent of rendering the work of perforation difficult to carry out or making the paper sheets slip out of their neat arrangement.